the SQL query. The ActorMigration class may also be used to get feature-flagged
information needed to access actor-related fields during the migration
period.
+* Added Wikimedia\Rdbms\IDatabase::cancelAtomic(), to roll back an atomic
+ section without having to roll back the whole transaction.
+* Wikimedia\Rdbms\IDatabase::doAtomicSection(), non-native ::insertSelect(),
+ and non-MySQL ::replace() and ::upsert() no longer roll back the whole
+ transaction on failure.
=== External library changes in 1.31 ===
return $this->__call( __FUNCTION__, func_get_args() );
}
+ public function cancelAtomic( $fname = __METHOD__ ) {
+ return $this->__call( __FUNCTION__, func_get_args() );
+ }
+
public function doAtomicSection( $fname, callable $callback ) {
return $this->__call( __FUNCTION__, func_get_args() );
}
* @see Database::trxLevel
*/
private $trxAutomatic = false;
+ /**
+ * Counter for atomic savepoint identifiers. Reset when a new transaction begins.
+ *
+ * @var int
+ */
+ private $trxAtomicCounter = 0;
/**
* Array of levels of atomicity within transactions
*
*/
private function handleSessionLoss() {
$this->trxLevel = 0;
+ $this->trxAtomicCounter = 0;
$this->trxIdleCallbacks = []; // T67263; transaction already lost
$this->trxPreCommitCallbacks = []; // T67263; transaction already lost
$this->sessionTempTables = [];
$this->endAtomic( $fname );
$this->affectedRowCount = $affectedRowCount;
} catch ( Exception $e ) {
- $this->rollback( $fname, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( $fname );
throw $e;
}
}
$this->endAtomic( $fname );
$this->affectedRowCount = $affectedRowCount;
} catch ( Exception $e ) {
- $this->rollback( $fname, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( $fname );
throw $e;
}
$this->endAtomic( $fname );
$this->affectedRowCount = $affectedRowCount;
} else {
- $this->rollback( $fname, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( $fname );
}
return $ok;
} catch ( Exception $e ) {
- $this->rollback( $fname, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( $fname );
throw $e;
}
}
call_user_func( $callback );
$this->endAtomic( __METHOD__ );
} catch ( Exception $e ) {
- $this->rollback( __METHOD__, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( __METHOD__ );
throw $e;
}
}
}
}
+ /**
+ * Create a savepoint
+ *
+ * This is used internally to implement atomic sections. It should not be
+ * used otherwise.
+ *
+ * @since 1.31
+ * @param string $identifier Identifier for the savepoint
+ * @param string $fname Calling function name
+ */
+ protected function doSavepoint( $identifier, $fname ) {
+ $this->query( 'SAVEPOINT ' . $this->addIdentifierQuotes( $identifier ), $fname );
+ }
+
+ /**
+ * Release a savepoint
+ *
+ * This is used internally to implement atomic sections. It should not be
+ * used otherwise.
+ *
+ * @since 1.31
+ * @param string $identifier Identifier for the savepoint
+ * @param string $fname Calling function name
+ */
+ protected function doReleaseSavepoint( $identifier, $fname ) {
+ $this->query( 'RELEASE SAVEPOINT ' . $this->addIdentifierQuotes( $identifier ), $fname );
+ }
+
+ /**
+ * Rollback to a savepoint
+ *
+ * This is used internally to implement atomic sections. It should not be
+ * used otherwise.
+ *
+ * @since 1.31
+ * @param string $identifier Identifier for the savepoint
+ * @param string $fname Calling function name
+ */
+ protected function doRollbackToSavepoint( $identifier, $fname ) {
+ $this->query( 'ROLLBACK TO SAVEPOINT ' . $this->addIdentifierQuotes( $identifier ), $fname );
+ }
+
final public function startAtomic( $fname = __METHOD__ ) {
if ( !$this->trxLevel ) {
$this->begin( $fname, self::TRANSACTION_INTERNAL );
if ( !$this->getFlag( self::DBO_TRX ) ) {
$this->trxAutomaticAtomic = true;
}
+ $savepointId = null;
+ } else {
+ $savepointId = 'wikimedia_rdbms_atomic' . ++$this->trxAtomicCounter;
+ if ( strlen( $savepointId ) > 30 ) { // 30 == Oracle's identifier length limit (pre 12c)
+ $this->queryLogger->warning(
+ 'There have been an excessively large number of atomic sections in a transaction'
+ . " started by $this->trxFname, reusing IDs (at $fname)",
+ [ 'trace' => ( new RuntimeException() )->getTraceAsString() ]
+ );
+ $this->trxAtomicCounter = 0;
+ $savepointId = 'wikimedia_rdbms_atomic' . ++$this->trxAtomicCounter;
+ }
+ $this->doSavepoint( $savepointId, $fname );
}
- $this->trxAtomicLevels[] = $fname;
+ $this->trxAtomicLevels[] = [ $fname, $savepointId ];
}
final public function endAtomic( $fname = __METHOD__ ) {
if ( !$this->trxLevel ) {
throw new DBUnexpectedError( $this, "No atomic transaction is open (got $fname)." );
}
- if ( !$this->trxAtomicLevels ||
- array_pop( $this->trxAtomicLevels ) !== $fname
- ) {
+
+ list( $savedFname, $savepointId ) = $this->trxAtomicLevels
+ ? array_pop( $this->trxAtomicLevels ) : [ null, null ];
+ if ( $savedFname !== $fname ) {
throw new DBUnexpectedError( $this, "Invalid atomic section ended (got $fname)." );
}
- if ( !$this->trxAtomicLevels && $this->trxAutomaticAtomic ) {
+ if ( !$savepointId ) {
$this->commit( $fname, self::FLUSHING_INTERNAL );
+ } else {
+ $this->doReleaseSavepoint( $savepointId, $fname );
}
}
+ final public function cancelAtomic( $fname = __METHOD__ ) {
+ if ( !$this->trxLevel ) {
+ throw new DBUnexpectedError( $this, "No atomic transaction is open (got $fname)." );
+ }
+
+ list( $savedFname, $savepointId ) = $this->trxAtomicLevels
+ ? array_pop( $this->trxAtomicLevels ) : [ null, null ];
+ if ( $savedFname !== $fname ) {
+ throw new DBUnexpectedError( $this, "Invalid atomic section ended (got $fname)." );
+ }
+
+ if ( !$savepointId ) {
+ $this->rollback( $fname, self::FLUSHING_INTERNAL );
+ } else {
+ $this->doRollbackToSavepoint( $savepointId, $fname );
+ }
+
+ $this->affectedRowCount = 0; // for the sake of consistency
+ }
+
final public function doAtomicSection( $fname, callable $callback ) {
$this->startAtomic( $fname );
try {
$res = call_user_func_array( $callback, [ $this, $fname ] );
} catch ( Exception $e ) {
- $this->rollback( $fname, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( $fname );
throw $e;
}
$this->endAtomic( $fname );
// Protect against mismatched atomic section, transaction nesting, and snapshot loss
if ( $this->trxLevel ) {
if ( $this->trxAtomicLevels ) {
- $levels = implode( ', ', $this->trxAtomicLevels );
+ $levels = array_reduce( $this->trxAtomicLevels, function ( $accum, $v ) {
+ return $accum === null ? $v[0] : "$accum, " . $v[0];
+ } );
$msg = "$fname: Got explicit BEGIN while atomic section(s) $levels are open.";
throw new DBUnexpectedError( $this, $msg );
} elseif ( !$this->trxAutomatic ) {
$this->assertOpen();
$this->doBegin( $fname );
+ $this->trxAtomicCounter = 0;
$this->trxTimestamp = microtime( true );
$this->trxFname = $fname;
$this->trxDoneWrites = false;
final public function commit( $fname = __METHOD__, $flush = '' ) {
if ( $this->trxLevel && $this->trxAtomicLevels ) {
// There are still atomic sections open. This cannot be ignored
- $levels = implode( ', ', $this->trxAtomicLevels );
+ $levels = array_reduce( $this->trxAtomicLevels, function ( $accum, $v ) {
+ return $accum === null ? $v[0] : "$accum, " . $v[0];
+ } );
throw new DBUnexpectedError(
$this,
"$fname: Got COMMIT while atomic sections $levels are still open."
return false;
}
+ protected function doSavepoint( $identifier, $fname ) {
+ $this->query( 'SAVE TRANSACTION ' . $this->addIdentifierQuotes( $identifier ), $fname );
+ }
+
+ protected function doReleaseSavepoint( $identifier, $fname ) {
+ // Not supported. Also not really needed, a new doSavepoint() for the
+ // same identifier will overwrite the old.
+ }
+
+ protected function doRollbackToSavepoint( $identifier, $fname ) {
+ $this->query( 'ROLLBACK TRANSACTION ' . $this->addIdentifierQuotes( $identifier ), $fname );
+ }
+
/**
* Begin a transaction, committing any previously open transaction
* @param string $fname
/**
* Begin an atomic section of statements
*
- * If a transaction has been started already, just keep track of the given
- * section name to make sure the transaction is not committed pre-maturely.
- * This function can be used in layers (with sub-sections), so use a stack
- * to keep track of the different atomic sections. If there is no transaction,
- * start one implicitly.
+ * If a transaction has been started already, sets a savepoint and tracks
+ * the given section name to make sure the transaction is not committed
+ * pre-maturely. This function can be used in layers (with sub-sections),
+ * so use a stack to keep track of the different atomic sections. If there
+ * is no transaction, one is started implicitly.
*
* The goal of this function is to create an atomic section of SQL queries
* without having to start a new transaction if it already exists.
*
- * All atomic levels *must* be explicitly closed using IDatabase::endAtomic(),
- * and any database transactions cannot be began or committed until all atomic
- * levels are closed. There is no such thing as implicitly opening or closing
- * an atomic section.
+ * All atomic levels *must* be explicitly closed using IDatabase::endAtomic()
+ * or IDatabase::cancelAtomic(), and any database transactions cannot be
+ * began or committed until all atomic levels are closed. There is no such
+ * thing as implicitly opening or closing an atomic section.
*
* @since 1.23
* @param string $fname
*/
public function endAtomic( $fname = __METHOD__ );
+ /**
+ * Cancel an atomic section of SQL statements
+ *
+ * This will roll back only the statements executed since the start of the
+ * most recent atomic section, and close that section. If a transaction was
+ * open before the corresponding startAtomic() call, any statements before
+ * that call are *not* rolled back and the transaction remains open. If the
+ * corresponding startAtomic() implicitly started a transaction, that
+ * transaction is rolled back.
+ *
+ * Note that a call to IDatabase::rollback() will also roll back any open
+ * atomic sections.
+ *
+ * @since 1.31
+ * @see IDatabase::startAtomic
+ * @param string $fname
+ * @throws DBError
+ */
+ public function cancelAtomic( $fname = __METHOD__ );
+
/**
* Run a callback to do an atomic set of updates for this database
*
* - This database object
* - The value of $fname
*
- * If any exception occurs in the callback, then rollback() will be called and the error will
- * be re-thrown. It may also be that the rollback itself fails with an exception before then.
- * In any case, such errors are expected to terminate the request, without any outside caller
- * attempting to catch errors and commit anyway. Note that any rollback undoes all prior
- * atomic section and uncommitted updates, which trashes the current request, requiring an
- * error to be displayed.
+ * If any exception occurs in the callback, then cancelAtomic() will be
+ * called to back out any statements executed by the callback and the error
+ * will be re-thrown. It may also be that the cancel itself fails with an
+ * exception before then. In any case, such errors are expected to
+ * terminate the request, without any outside caller attempting to catch
+ * errors and commit anyway.
*
- * This can be an alternative to explicit startAtomic()/endAtomic() calls.
+ * This can be an alternative to explicit startAtomic()/endAtomic()/cancelAtomic() calls.
*
* @see Database::startAtomic
* @see Database::endAtomic
+ * @see Database::cancelAtomic
*
* @param string $fname Caller name (usually __METHOD__)
* @param callable $callback Callback that issues DB updates
* @throws DBError
* @throws RuntimeException
* @throws UnexpectedValueException
- * @since 1.27
+ * @since 1.27; prior to 1.31 this did a rollback() instead of
+ * cancelAtomic(), and assumed no callers up the stack would ever try to
+ * catch the exception.
*/
public function doAtomicSection( $fname, callable $callback );
$this->assertSame( 'CAST( fieldName AS INTEGER )', $output );
}
+ /**
+ * @covers \Wikimedia\Rdbms\Database::doSavepoint
+ * @covers \Wikimedia\Rdbms\Database::doReleaseSavepoint
+ * @covers \Wikimedia\Rdbms\Database::doRollbackToSavepoint
+ * @covers \Wikimedia\Rdbms\Database::startAtomic
+ * @covers \Wikimedia\Rdbms\Database::endAtomic
+ * @covers \Wikimedia\Rdbms\Database::cancelAtomic
+ * @covers \Wikimedia\Rdbms\Database::doAtomicSection
+ */
+ public function testAtomicSections() {
+ $this->database->startAtomic( __METHOD__ );
+ $this->database->endAtomic( __METHOD__ );
+ $this->assertLastSql( 'BEGIN; COMMIT' );
+
+ $this->database->startAtomic( __METHOD__ );
+ $this->database->cancelAtomic( __METHOD__ );
+ $this->assertLastSql( 'BEGIN; ROLLBACK' );
+
+ $this->database->begin( __METHOD__ );
+ $this->database->startAtomic( __METHOD__ );
+ $this->database->endAtomic( __METHOD__ );
+ $this->database->commit( __METHOD__ );
+ // phpcs:ignore Generic.Files.LineLength
+ $this->assertLastSql( 'BEGIN; SAVEPOINT wikimedia_rdbms_atomic1; RELEASE SAVEPOINT wikimedia_rdbms_atomic1; COMMIT' );
+
+ $this->database->begin( __METHOD__ );
+ $this->database->startAtomic( __METHOD__ );
+ $this->database->cancelAtomic( __METHOD__ );
+ $this->database->commit( __METHOD__ );
+ // phpcs:ignore Generic.Files.LineLength
+ $this->assertLastSql( 'BEGIN; SAVEPOINT wikimedia_rdbms_atomic1; ROLLBACK TO SAVEPOINT wikimedia_rdbms_atomic1; COMMIT' );
+
+ $this->database->startAtomic( __METHOD__ );
+ $this->database->startAtomic( __METHOD__ );
+ $this->database->cancelAtomic( __METHOD__ );
+ $this->database->endAtomic( __METHOD__ );
+ // phpcs:ignore Generic.Files.LineLength
+ $this->assertLastSql( 'BEGIN; SAVEPOINT wikimedia_rdbms_atomic1; ROLLBACK TO SAVEPOINT wikimedia_rdbms_atomic1; COMMIT' );
+
+ $this->database->doAtomicSection( __METHOD__, function () {
+ } );
+ $this->assertLastSql( 'BEGIN; COMMIT' );
+
+ $this->database->begin( __METHOD__ );
+ $this->database->doAtomicSection( __METHOD__, function () {
+ } );
+ $this->database->rollback( __METHOD__ );
+ // phpcs:ignore Generic.Files.LineLength
+ $this->assertLastSql( 'BEGIN; SAVEPOINT wikimedia_rdbms_atomic1; RELEASE SAVEPOINT wikimedia_rdbms_atomic1; ROLLBACK' );
+
+ $this->database->begin( __METHOD__ );
+ try {
+ $this->database->doAtomicSection( __METHOD__, function () {
+ throw new RuntimeException( 'Test exception' );
+ } );
+ $this->fail( 'Expected exception not thrown' );
+ } catch ( RuntimeException $ex ) {
+ $this->assertSame( 'Test exception', $ex->getMessage() );
+ }
+ $this->database->commit( __METHOD__ );
+ // phpcs:ignore Generic.Files.LineLength
+ $this->assertLastSql( 'BEGIN; SAVEPOINT wikimedia_rdbms_atomic1; ROLLBACK TO SAVEPOINT wikimedia_rdbms_atomic1; COMMIT' );
+ }
+
+ public static function provideAtomicSectionMethodsForErrors() {
+ return [
+ [ 'endAtomic' ],
+ [ 'cancelAtomic' ],
+ ];
+ }
+
+ /**
+ * @dataProvider provideAtomicSectionMethodsForErrors
+ * @covers \Wikimedia\Rdbms\Database::endAtomic
+ * @covers \Wikimedia\Rdbms\Database::cancelAtomic
+ */
+ public function testNoAtomicSection( $method ) {
+ try {
+ $this->database->$method( __METHOD__ );
+ $this->fail( 'Expected exception not thrown' );
+ } catch ( DBUnexpectedError $ex ) {
+ $this->assertSame(
+ 'No atomic transaction is open (got ' . __METHOD__ . ').',
+ $ex->getMessage()
+ );
+ }
+ }
+
+ /**
+ * @dataProvider provideAtomicSectionMethodsForErrors
+ * @covers \Wikimedia\Rdbms\Database::endAtomic
+ * @covers \Wikimedia\Rdbms\Database::cancelAtomic
+ */
+ public function testInvalidAtomicSectionEnded( $method ) {
+ $this->database->startAtomic( __METHOD__ . 'X' );
+ try {
+ $this->database->$method( __METHOD__ );
+ $this->fail( 'Expected exception not thrown' );
+ } catch ( DBUnexpectedError $ex ) {
+ $this->assertSame(
+ 'Invalid atomic section ended (got ' . __METHOD__ . ').',
+ $ex->getMessage()
+ );
+ }
+ }
+
}
dépôts / lhc / web / wiklou.git / commitdiff